Essentially a wave equation, the Schrödinger equation describes the form of the probability waves (or wave functions [seede Broglie wave]) that govern the motion of small particles, and it specifies how these waves are altered by external influences. Schrödinger established the correctness of the equation by applying it to the hydrogenatom, predicting many of its properties with remarkable accuracy. The equation is used extensively in atomic, nuclear, and solid-state physics. (For a fuller treatment of the Schrödinger equation, seequantum mechanics: Schrödinger’s wave mechanics.)